Protein in diet

Definition

Proteins are the building blocks of life. The body needs protein to repair and maintain itself. The basic structure of protein is a chain of amino acids.

Alternative Names

Diet - protein; Complete protein; Incomplete protein

Function

Every cell in the human body contains protein. It is a major part of the skin, muscles, organs, and glands. Protein is also found in all body fluids, except bile and urine.

You need protein in your diet to help your body repair cells and make new ones. Protein is also important for growth and development during childhood, adolescence, and pregnancy.

Food Sources

When proteins are digested, amino acids are left. The human body needs a number of amino acids to break down food. Amino acids need to be eaten in large enough amounts for optimal health.

Amino acids are found in animal sources such as meats, milk, fish, and eggs, as well as in plant sources such as soy, beans, legumes, nut butters, and some grains (such as wheat germ). You do not need to eat animal products to get all the protein you need in your diet.

Amino acids are classified into three groups:

Essential

Nonessential

Conditional

Essential amino acids cannot be made by the body, and must be supplied by food. They do not need to be eaten at one meal. The balance over the whole day is more important. The nine essential amino acids are:

Histidine

Isoleucine

Leucine

Lycine

Methionine

Phenylalanine

Threonine

Tryptophan

Valine

Nonessential amino acids are made by the body from essential amino acids or in the normal breakdown of proteins. They include:

Alanine

Asparagine

Aspartic acid

Glutamic acid

Conditional amino acids are usually not essential, except in times of illness and stress. They include:

Arginine

Cysteine

Glutamine

Glycine

Ornithine

Proline

Serine

Tyrosine

Protein foods are no longer described as being "complete proteins" or "incomplete proteins."

Side Effects

A diet high in meat can contribute to high cholesterol levels or other diseases such as gout. A high-protein diet may also put a strain on the kidneys.